黄酮类活性成分对吸烟致质粒DNA损伤的保护作用

目的评价吸烟致质粒DNA损伤以及黄酮类活性成分对其损伤的防护作用。方法以自动吸烟机按照FTC协议吸烟产生的主流烟雾在线染毒溶液状态超螺旋构象质粒DNA,通过琼脂糖凝胶电泳分析DNA分子构象变化,检测DNA损伤程度及黄酮类活性成分黄芩素、槲皮素、丹参素钠及淫羊藿苷的防护作用。结果体外在线吸烟可致质粒DNA明显损伤,随吸烟剂量由0增加到8 puff及DNA与烟雾作用时间由0增加到1.3 h,DNA的断链分数F由0.15分别增加到0.24及0.29。即使在大剂量的烟雾攻击下,3种活性成分黄芩素、槲皮素与丹参素钠浓度〈0.001mol L-1时,均能够有效减轻吸烟对质粒DNA的损伤,与单独吸烟组相比,质粒DNA开环构象显著减少,在一定范围内,保护效果随着药物浓度的增加更加明显。结论黄芩素、槲皮素与丹参素钠对吸烟导致的DNA损伤具有较好的保护作用,其保护效果呈浓度依赖性。     

丹参中水溶性成分丹参素钠的HPLC测定

目的:建立丹参中水溶性成分丹参素钠的含量测定方法.方法:采用HPLC法,色谱柱为Shimadzu ODS C18(250 mm×4.6 mm,5μm),以甲醇-水-冰醋酸(8:91:1)为流动相,流速1.0 ml·min-1,检测波长281 nm.结果:丹参素钠在5.9～29.5μg·ml-1的浓度范围内与其峰面积呈良好的线性关系(r=0.999 9),平均回收率为97.0%(RSD=0.6%,n=6).结论:该方法操作简便、结果可靠,重复性好,可用于丹参中水溶性成分丹参素钠的分析.     

韧黄芩中黄酮类成分的研究

黄芩属植物我国有100多种,多为野生,南北均产。药用黄芩为唇形科黄芩属多种植物干燥的根,不是单一品种,主产于北方的有3种,主产于南方的有4、5种。而正品黄芩     

黄芩素对过氧化氢致PC12细胞损伤的保护作用研究

目的:研究黄芩素(BAI)对过氧化氢(H2O2)损伤的神经细胞的保护作用。方法:用体外细胞培养法,预先孵育24h,以500μmol·L-1H2O2复制大鼠肾上腺髓质嗜铬瘤分化细胞株(PC12)不可逆氧化损伤模型,观察BAI对其影响,并在损伤时分为移除药物和不移除药物2种情况进行分析;通过MTT微量比色法测定细胞活度,并测定培养液中乳酸脱氢酶(LDH)的含量。结果:预先给予BAI作用24h后,在造模时不论是否移除药物,BAI对损伤细胞均有显著的保护作用,尤以不移除药物的效果更为显著。镜下观察,BAI组细胞形态出现一定程度上的边缘模糊,单个细胞体积变大,有少许细胞融合的状态发生;MTT法测定细胞活度升高,培养液中LDH含量降低,与模型组比较差异显著。结论:BAI能显著减轻PC12细胞损伤,其作用机制可能在氧化-抗氧化环节,与BAI能够减轻呼吸链阻断造成的自由基堆积、抗氧化和清除自由基的能力有关。     

丹参素钠通过抑制炎症反应对心肌缺血-再灌注损伤的保护作用

目的探讨丹参素钠通过抑制炎症反应对大鼠心肌缺血-再灌注(myocardial ischemia-reperfusion,MI/R)损伤的保护作用。方法采用结扎冠状动脉复制大鼠MI/R损伤模型,将动物随机分为假手术组,模型组,丹参素钠低、中、高剂量组。除模型组于再灌注时给予生理盐水外,丹参素钠低、中、高剂量组于再灌注即刻给予丹参素钠(15、30、60 mg kg-1)。实验终末,测定心肌梗死面积,检测血清中肌酸激酶同工酶(CK-MB)、肌钙蛋白(cTnI)、肿瘤坏死因子(TNF-α)、白细胞介素1(IL-1)和白细胞介素6(IL-6)水平,采用苏木精-伊红染色法(HE)观察心肌组织的病理性改变。结果与模型组相比,丹参素钠中、高剂量组大鼠心肌梗死面积显著减少(P<0.05),血清中CK-MB、cTnI的浓度显著下降(P<0.05),并且丹参素钠高剂量组TNF-α、IL-1、IL-6均显著小于模型组(P<0.05),所有给药组心肌组织的病理损伤也小于模型组。结论丹参素钠对大鼠MI/R损伤有保护作用,其机制与抑制MI/R损伤时的炎症反应相关。     

黄芩提取物及黄酮类化合物对肺癌作用机制的研究进展

目的：为深入研究黄芩对肺癌的抗肿瘤作用机制提供参考。方法查阅国、内外关于黄芩提取物及黄酮类化合物对肺癌抗肿瘤作用的文献并综述其研究成果。结果黄芩提取物及黄酮类化合物对肺癌的抗肿瘤作用主要通过诱导细胞凋亡,阻断细胞周期,清除肺癌自由基、活性氧簇,抑制肺癌转移,逆转肺癌多药耐药,影响花生四烯酸的代谢,抑制核因子κB（NF -κB）活性,抑制端粒酶等多种机制。结论随着黄芩提取物及黄酮类化合物对肺癌抗肿瘤作用机制的研究不断深入,有望从其中开发出新的抗肺癌药物。     

黄芩苷对香烟烟雾提取物诱导的细胞损伤保护作用研究

目的研究黄芩苷对香烟烟雾提取物（cigarette smoke extract,CSE）诱导的人肺泡上皮细胞损伤的影响,并初步探讨其机制。方法制备CSE,用不同浓度黄芩苷对人肺泡上皮细胞A549进行预处理,再用CSE刺激细胞。用MTT法检测细胞存活率,流式细胞术测定细胞凋亡率,彗星实验观察DNA损伤情况,荧光法测定细胞内活性氧（reactive oxygen species,ROS）含量。结果随着CSE浓度的增加和作用时间的延长,细胞存活率下降,各组之间有统计学差异（P〈0.05）;黄芩苷能减少CSE诱导的细胞存活率下降,抑制CSE诱导的细胞内ROS的产生,并有剂量依赖关系（P〈0.05或P〈0.01）;黄芩苷＋CSE组细胞的彗星尾长、尾部DNA含量、尾距、Olive尾距均小于CSE组（P〈0.05）,并且黄芩苷可以减少CSE导致的细胞凋亡。结论黄芩苷可以拮抗CSE对细胞的损伤,提高细胞的存活率,降低凋亡率,其原因可能与黄芩苷能降低细胞ROS含量,减少DNA损伤有关。     

槲皮素对缺血性心肌损伤保护作用的研究

目的：观察槲皮素对缺血性心肌损伤的保护作用。方法：将大鼠随机分为空白组、模型组、阳性对照组和实验组,皮下注射异丙肾上腺素（Isoprenaline,Is0）造成缺血性心肌损伤模型后,观察心电图（ECG）的变化。检测大鼠心肌组织中丙二醛（MDA）和超氧化物歧化酶（s0D）的含量。结果：槲皮素可明显降低心肌组织中MDA的含量,提高SOD活性,并使ISO导致ECG抬高的J点位移降低。结论：槲皮素对ISO导致的缺血性心肌损伤有明显的保护作用。     

汉黄芩素对大鼠致畸敏感期的毒性试验

目的：观察汉黄芩素对大鼠致畸敏感期的毒性反应。方法：将SD大鼠随机分为4组,每组16只,设空白对照组和汉黄芩素40,13．3,4．4mg·kg^-1剂量组,在受孕大鼠致畸敏感期（受孕第6～15d）给药,观察各组孕鼠的毒性情况。结果：汉黄芩素高剂量组孕鼠体重增长缓慢,躯干骨的胸骨数、骶尾椎数,前肢手掌骨的中手骨数、指骨总数和后肢脚掌骨的中足骨数、趾骨总数减少,与空白对照组相比差异也有显著性意义;高、中剂量组胎鼠的头顶骨、侧头骨和后头骨骨化不全数,与空白对照组相比差异有显著性意义（P〈0．01）。结论：未发现汉黄芩素对胎鼠有明显致畸作用。但该药高剂量可使胎鼠骨骼发育迟缓。     

Inhibition of immunological function mediated DNA damage of alveolar macrophages caused by cigarette smoke in mice

Exposure to cigarette smoke impairs the pulmonary immune system, including alveolar macrophage function, although the mechanisms by which this occurs are not fully elucidated. This study investigates the effect of cigarette smoke exposure on the antigen-presenting activity of alveolar macrophages, which is required for antigen-specific response to T cells. C57BL/6 mice were exposed to cigarette smoke for 10 days using a Hamburg II smoking machine, and alveolar macrophages were obtained by bronchoalveolar lavage. The antigen-presenting activity of alveolar macrophages was significantly inhibited in mice exposed to cigarette smoke compared with mice not exposed to cigarette smoke. Major histocompatibility complex class II cell surface molecule–positive cells, B7-1 molecule–positive cells, and interleukin-1β messenger RNA gene expression in alveolar macrophages were significantly decreased in mice exposed to cigarette smoke compared with mice not exposed to cigarette smoke. In contrast, DNA damage and generation of superoxide and hydrogen peroxide in alveolar macrophages were significantly increased by cigarette smoke exposure. These results suggest that inhibition of the antigen-presenting activity of alveolar macrophages may result from decreased expression of major histocompatibility complex class II and B7-1 molecules and interleukin-1β messenger RNA gene expression following cigarette smoke exposure. Furthermore, inhibition of antigen presentation in alveolar macrophage may result from DNA damage induced by excessive amounts of reactive oxygen species being generated by alveolar macrophages following cigarette smoke exposure. These findings suggest that cigarette smoke impairs the immunological function of alveolar macrophages and, as a result, increases the risk for pulmonary infection.     

Effect of smoking conditions and methods of collection on the mutagenicity and cytotoxicity of cigarette mainstream smoke.

There is a history for the use of in vitro bioassays to assess the toxicological properties of mainstream cigarette smoke (MSS). The results described in the literature were, for the most part, obtained with MSS collected under Federal Trade Commission (FTC) or International Organization for Standardization (ISO) conditions. However, numerous studies have shown that smokers smoke their cigarettes more intensely (e.g., they take larger puffs and/or more frequent puffs and/or partially occlude filter ventilation) than they are smoked on smoking machines operated under FTC (or ISO) conditions. It has also been reported that MSS composition changes with changes in smoking conditions. Furthermore, some governmental agencies have adopted regulations that specify more intensive protocols (i.e., Health Canada Intensive, HCI) for the collection of MSS for in vitro toxicological assays. Consequently, the performance of the Ames assay (TA98+S9, TA100+S9) and neutral red uptake assay under ISO and HCI protocols was studied with two blended (KR1R4F/KR2R4F, KR1R5F) and one flue-cured (CIM-7) reference cigarettes. The main outcome was when results were reported on a per milligram TPM (that portion of the mainstream smoke which is trapped in the smoke trap, expressed as milligrams per cigarette) basis generated under ISO conditions was more mutagenic and more cytotoxic than was TPM generated under HCI conditions. However, the decrease in biological activity could not be explained only by the increased in the water content of the TPM on going from ISO to HCI smoking conditions, and the results may be influenced by differences in smoke chemistry as a result of differing smoke collection systems.     

Evaluation of DNA damage and cytotoxicity induced by three commonly used organophosphate pesticides individually and in mixture,in rat tissues

Organophosphate pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (CPF), methyl parathion (MPT), and malathion (MLT) are among the most extensively used organophosphate (OP) pesticides. The main target of action of OP compounds is the central and peripheral nervous system, although it has also been postulated that these compounds in both acute and chronic intoxication, disturb the redox processes and thus induce oxidative stress. The excessive generation of reactive oxygen species (ROS) causes damage to all vital macromolecules including lipids, proteins, and DNA. This study was aimed to investigate the genotoxicity and cytotoxicity of CPF, MPT, and MLT when given singly or in combination. The DNA damage was measured by alkaline single‐cell gel electrophoresis or comet assay and expressed as DNA damage index. The results showed that both acute and chronic exposure with CPF, MPT, and MLT, caused significantly marked DNA damage in rat tissues namely, liver, brain, kidney, and spleen, when measured 24 hour posttreatment. It was also observed that MPT caused highest level of DNA damage and brain was maximally affected by these OP compounds. When these pesticides were given in mixture, the damage was not the sum of damage caused by individual pesticide, confirming that these pesticides do not potentiate the toxicity of each other. When the DNA damage was measured 48 and 72 hour posttreatment, the damage was partially repaired. Pesticide exposure also caused histopathological changes in rat tissues. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 543–552, 2013.     

Enantiomer‐specific profenofos‐induced cytotoxicity and DNA damage mediated by oxidative stress in rat adrenal pheochromocytoma (PC12) cells

Recent studies have shown that chiral pesticides could enantioselectively induce cytotoxicity and genotoxicity. However, investigations on molecular mechanisms of enantioselective toxicity of pesticides are limited. In this study, the role of oxidative stress in enantiomer‐specific, profenofos (PFF)‐induced cytotoxicity and genotoxicity was investigated using PC12 cells. The results demonstrated that PFF enantioselectively reduced cell viability and induced DNA damage in PC12 cells. A concentration‐ and time‐dependent significant induction of reactive oxygen species (ROS), malondialdehyde and gene expression encoding antioxidant enzyme (Cu‐ZnSOD, GST and CAT) and stress protein (HSP 70 and HSP 90) was observed in (?)­PFF, whereas (+)­PFF and rac‐PFF exhibited these effects to lesser degrees. Pre‐treatment with vitamin E (600 μM) caused a significant attenuation in the toxic effect; reversing subsequent PFF‐induced elevation of ROS and malondialdehyde (MDA) levels, further strengthening the involvement of oxidative stress in PFF‐mediated toxicity. In addition, the results also showed that PFF‐dependent ROS accumulation, MDA release and oxidative stress gene expression preceded the loss of cell viability and induction of DNA damage, and already significantly changed at concentrations which are not yet cytotoxic or genotoxic. These results indicate that oxidative stress may contribute to PFF‐induced toxicity and that it was not a consequence of it. Copyright © 2013 John Wiley & Sons, Ltd.     

Direct‐oxidative DNA damage and apoptosis induction in different human respiratory cells exposed to low concentrations of sodium chromate

The mechanism of Cr(VI) genotoxicity has still not been elucidated. We used Fpg‐modified comet assay to assess direct‐oxidative DNA damage on human lung (A549) and bronchial (BEAS‐2B) cells exposed to 0.1, 0.5, 1.0 and 10 μm sodium chromate for 0.5, 1 and 4 h. Moreover we evaluated apoptosis by morphological analysis and caspase‐3 activity, also after 24 h. On A549 cells a time‐dependent DNA damage, expressed as tail DNA%, beginning from 0.5 μm was found. For oxidative DNA damage an induction after 30 min to 0.5 μm decreasing with time, and a time‐dependent increase at 10 μm was found, indicating for low Cr(VI) concentration the oxidative stress as the first event followed by direct DNA damage and for the highest concentration a time‐dependent increase in oxidative DNA damage. On BEAS‐2B cells DNA damage was induced within 1 h at 0.5–10 μm , without changes with time, showing that BEAS‐2B cells are able to resist to Cr(VI) genotoxicity. Early oxidative DNA damage at 0.1 μm decreasing with time was also found. Significant apoptosis was observed by morphological analysis in A549 cells and to a lower extent in BEAS‐2B at 10 μm . The exposure to 10 μm induced caspase‐3 activity after 4 h in BEAS‐2B and after 24 h in A549 cells. The findings show a higher responsiveness of A549 cells to genotoxic effect of Cr(VI) and early transient oxidative DNA damage in BEAS‐2B. The results emphasize the suitability of this experimental model to evaluate the early genotoxic response of different cells to non‐cytotoxic concentrations of Cr(VI) on target organ. Copyright © 2009 John Wiley & Sons, Ltd.     

The kinetics of transcriptomic changes induced by cigarette smoke in rat lungs reveals a specific program of defense, inflammation, and circadian clock gene expression.

Gene expression profiling in animal models exposed to cigarette mainstream smoke (CS) shapes up as a promising tool for investigating the molecular mechanisms involved in the onset and development of CS-related disease and may aid in the identification of disease candidate genes. Here we report on differential gene expression in lungs of rats exposed for 2, 7, and 13 weeks to 300 and 600 microg total particulate matter/l CS with sacrifice 2, 6, or 20 h after the last exposure. Regarding antioxidant and xenobiotic-metabolizing (phase I/II) enzymes, a stereotypic, mostly transient, expression pattern of differentially expressed genes was observed after each exposure period. The expression patterns were generally dose dependent for antioxidant and phase II genes and not dose dependent for phase I genes at the CS concentrations tested. However, with increasing length of exposure, there was a distinct, mostly sustained and dose-sensitive, expression of genes implicated in innate and adaptive immune responses, clearly pointing to an emerging inflammatory response. Notably, this inflammatory response included the expression of lung disease-related genes not yet linked to CS exposure, such as galectin-3, arginase 1, and chitinase, as well as genes encoding proteolytic enzymes. Finally, our experiments also revealed a CS exposure-dependent shift in the cyclical expression of genes involved in controlling the circadian rhythm. Altogether, these results provide further insight into the molecular mechanisms of CS-dependent disease onset and development and thus may also be useful for defining CS-specific molecular biomarkers of disease.     

Influence of the surface coating on the cytotoxicity,genotoxicity and uptake of gold nanoparticles in human HepG2 cells

The toxicological profile of gold nanoparticles (AuNPs) remains controversial. Significant efforts to develop surface coatings to improve biocompatibility have been carried out. In vivo biodistribution studies have shown that the liver is a target for AuNPs accumulation. Therefore, we investigated the effects induced by ~20 nm spherical AuNPs (0–200 μM Au) with two surface coatings, citrate (Cit) compared with 11‐mercaptoundecanoic acid (11‐MUA), in human liver HepG2 cells. Cytotoxicity was evaluated using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) reduction and lactate dehydrogenase (LDH) release assays after 24 to 72 h of incubation. DNA damage was assessed by the comet assay, 24 h after incubation with the capped AuNPs. Uptake and subcellular distribution of the tested AuNPs was evaluated by quantifying the gold intracellular content by graphite furnace atomic absorption spectrometry (GFAAS) and transmission electron microscopy (TEM), respectively. The obtained results indicate that both differently coated AuNPs did not induce significant cytotoxicity. An inverse concentration‐dependent increase in comet tail intensity and tail moment was observed in Cit‐AuNPs‐ but not in MUA‐AuNPs‐exposed cells. Both AuNPs were internalized in a concentration‐dependent manner. However, no differences were found in the extent of the internalization between the two types of NPs. Electron‐dense deposits of agglomerates of Cit‐ and MUA‐AuNPs were observed either inside endosomes or in the intercellular spaces. In spite of the absence of cytotoxicity, DNA damage was observed after exposure to the lower concentrations of Cit‐ but not to MUA‐AuNPs. Thus, our data supports the importance of the surface properties to increase the biocompatibility and safety of AuNPs. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of cytogenetic and DNA damage induced by the antidepressant drug-active ingredients,trazodone and milnacipran,in vitro

Trazodone and milnacipran are the active antidepressant drugs that are being used in the treatment of psychiatric disorders. In this study, the in vitro genotoxic effects of trazodone and milnacipran have been determined in human peripheral blood lymphocytes by using chromosomal aberrations (CAs), sister chromatid exchanges (SCEs), micronuclei (MN), and comet assays. 3.13; 6.25; 12.50; 25.00; 50.00; and 75.00?μg/mL concentrations of trazodone and 2.50; 5.00; 10.00; 20.00; 30.00; and 40.00?μg/mL concentrations of milnacipran were used. Trazodone and milnacipran significantly increased the frequency of CAs and SCEs compared with the control. Both of the active ingredients raised the MN frequency in a dose-dependent manner. Mitotic index was significantly decreased, but replication and nuclear division indices were not affected at all treatments. Trazodone was statistically increased the mean comet tail intensity, tail length, and tail moment at three concentrations (6.25; 12.50; and 25.00?μg/mL) compared with control. Two highest concentrations (50 and 75?μg/mL) of trazodone were toxic in the comet assay. Milnacipran increased the comet tail intensity, tail length, and tail moment at all concentrations. It is concluded that trazodone and milnacipran have clastogenic, mutagenic, and cytotoxic effects on human lymphocytes in vitro.     

Protection of DNA and erythrocytes from free radical induced oxidative damage by black gram (Vigna mungo L.) husk extract

Antioxidants present in various plant tissues exhibit health benefits by scavenging reactive oxygen species generated under various pathophysiological conditions. In the present study, bioactive compounds from black gram husk were extracted with water and the protection of black gram husk (BGH) extract against oxidative damage in DNA and erythrocytes were studied. BGH extract had total polyphenol content of 59 mg of gallic acid equivalents (GAE). The phenolic acids identified in the extract using RP-HPLC were gallic, protocatechuic, gentisic and ferulic acids. The extract showed good antioxidant properties. The IC₅₀ value for DPPH radical scavenging activity was found to be 3.92 μg of GAE. The BGH extract also showed α-glucosidase inhibition and the IC₅₀ value was found to be 2.78 μg of GAE. The oxidative hemolysis caused by hydrogen peroxide in rat erythrocytes was inhibited by BGH extract in a dose dependent manner. The IC₅₀ values for BGH extract and BHA for hemolysis were 11.5 and 14 μg of GAE, respectively. Morphological changes in erythrocyte membrane caused by hydrogen peroxide were protected by BGH extract. As BGH extract exhibited various antioxidant properties in different systems, it could be used as a functional food or nutraceutical product for health benefits.